LT6201 datasheet(17/20 Pages) LINER

17 / 20 page

LTC2315-12

231512f

For more information www.linear.com/2315-12

applicaTions inForMaTion

For more details and information refer to DC1563A, the

evaluation kit for the LTC2315-12.

Bypassing Considerations

High quality tantalum and ceramic bypass capacitors

should be used at the VDD, OVDD and REF pins. For opti-

mum performance, a 2.2µF ceramic chip capacitor should

be used for the VDD and OVDD pins. The recommended

bypassing for the REF pin is also a low ESR, 2.2µF ceramic

capacitor. The traces connecting the pins and the bypass

capacitors must be kept as short as possible and should

be made as wide as possible avoiding the use of vias.

ThefollowingisanexampleofarecommendedPCBlayout.

All analog circuitry grounds should be terminated at the

LTC2315-12. The ground return from the LTC2315-12 to

the power supply should be low impedance for noise free

operation. Digital circuitry grounds must be connected to

the digital supply common.

In applications where the ADC data outputs and control

signals are connected to a continuously active micropro-

cessor bus, it is possible to get errors in the conversion

results. These errors are due to feed-through from the

microprocessor to the successive approximation com-

Figure 16. Top Silkscreen

Figure 17. Layer 1 Top Layer

Figure 18. Layer 2 GND Plane

parator. The problem can be eliminated by forcing the

microprocessor into a “Wait” state during conversion

or by using tri-state buffers to isolate the ADC data bus.

LT6201 Datasheet(PDF) 17 Page - Linear Technology